Copper base alloy



Patented June 14, 1949 NITED STATES COPPER BASE ALLOY No Drawing.Application December 10, 1946,

Serial No. 715,335

7 Claims. (01. 75-159) This invention relates to copper base alloysreferring more particularly to copper base alloys especially useful fordeposition by welding methods and having when so deposited unusuallyhigh hardness and resistance to wear.

The use of copper base alloys for joining steel, cast iron or cuprousmembers by welding or brazing is widespread because or the ease withwhich sound strong joints may be attained. Some copper base materialsare used for the purpose of rebuilding worn surfaces such as valveseats, and quite often new articles are protected by a surface layer ofcopper base material deposited by welding or brazing. The success withwhich these methods have met has led to a demand for their use in moreextensive and more difilcult applications, and there is consequently a,demand for copper base materials having higher hardness and greaterresistance to Wear than is possessed by the materials now commerciallyavailable.

It is the principal object of this invention to provide a copper basealloy which satisfies this demand. More specifically, the invention hasfor its primary object the provision of a copper base alloy adapted todeposition by welding or brazing methods which, when so deposited, has ahigh hardness, and improved resistance to wear and retains its highhardness at moderately elevated temperatures.

The invention by means of which this object is attained comprises acopper base alloy, and welding rods fabricated therefrom, containingcritical proportions of nickel, zinc, tin and silicon. The alloy of theinvention contains 23% to 30% nickel; 25% to 35% zinc; 5% to tin; 0.01%to 0.5% silicon; the remainder substantially all copper, and the sum ofthe zinc and tin contents being 35% to 4 of the alloy. A preferred rangeof constituents is to 27% nickel; 8% to 10% tin; 29% to 33% zinc; 0.2%to 0.4% silicon; the remainder copper and the sum of the tin and zinccontents being 37% to less than 41% of the alloy. A specific compositioncontains 25% to 27% nickel; 8.5% to 9.5% tin; to 32% zinc; 0.2% to 0.4%silicon and the remainder copper. The invention also includes metalarticles exposed to wear, at least those portions of such articlessubjected to wear being composed of the alloy described.

The alloys within the composition ranges just disclosed are readilydeposited by orthodox welding procedures; have good flowing properties;show little evidence of the fuming which is a disadvantage of somecopper base materials when deposited by welding; and form strong,nonporous deposits exhibiting excellent adherence to steel, cast iron orcuprous members. The melting point of alloys within the compositionranges disclosed is below 950 (1., generally being about 930 C. TheBrinell hardness of deposits of alloys of this composition is of theorder of 275 (3000 kg. load) at room temperature, and the Brinellhardness of the alloys as deposited is about to at a temperature of 430C.

As will be seen from the above statements the alloy of the invention hasproperties which recommend it for use in hard surfacing operations, forexample in the building up of wearresisting pads on machine tools;non-galling pads on door dogs; non-scoring pressure edges indeep-drawing dies; and many Wear-resisting surfaces on railroad rollingstock. Because of its retention of hardness at moderately elevatedtemperatures the alloy is also well suited to use in the provision ofWear-resisting surfaces exposed to elevated temperatures such as wristpin bearings, seats for steam valves and lands on steam engine pistons.Since the alloy also exhibits eX- cellent resistance to corrosion it isuseful for the production of corrosion-resisting non-scoring valveseats. Because of the silvery color of the alloy it is particularlysuitable for the welding or brazing or hard surfacing of nickel orferrous alloys where it is desired that the color of the depositedmaterial be similar to that of the base.

As is indicated above, the composition limits of the invention and theproportioning of the constituents with respect to one another arecritical. If the sum of the zinc and tin contents is less than 35% ofthe alloy, the requisite hardness is not attained. On the other hand, ifthe sum of the Zinc and tin contents is more than 41% of the alloy, thedeposit produced by welding exhibits undesirable brittleness. Theproportion of nickel in the alloy is important; if less than about 23%is present the deposited material does not have the desired hardness andthe adherence of the deposit to steel or cast iron is not as good as isdesired. Too high a nickel content, however, tends to raise the meldingpoint undesirably. A high tin content on the other hand, tends toovercome the melting point raising effect of nickel. The presence ofsilicon in the alloy is important, silicon minimizing fuming of themolten alloy during deposition. Iron, a common impurity in copper basealloys, may be present in the alloy of the invention as an impurity, butif more than about 0.3% is present, the alloy tends to become sluggishwhen molten for deposition, and to develop porosity when deposited. Theiron content therefore should be well below 1% and preferably less than0.3%.

Specific examples of alloys within the composition limits of theinvention are set forth in the following table, which also indicates theBrinell hardness measured at the temperatures indicated in the tablewith a 3000 kg. load.

Composition: Remainder Copper figf g Percent Percent Percent PercentRoom Nickel Tin Zinc Silicon Temp.

23. s. 3 32. 3 0. 48 292 143 121 24. 5 30 0. 5 295 ms 121 7 31 0.2 24025 9. 5 s1 0. 2 280 (0 25 1o 0. 2 274 22 5 33 0.2 230 26 1o. 5 25. 5 0.2228 (0 26 10. 5 2s. 5 0.2 269 g 25 5. 5 34. 5 0. 2 290 1 Not tested.

Weld deposits having the compositions set forth in the abov table wereall sound, being free from cracks, and adhered strongly to the steelbase on which they were formed. The melting point of th weld metalaveraged about 930 C.

While specific examples of the composition of the alloy of the inventionand of specific applications for its use have been given, the inventionis not limited to these particular examples or particular uses, but ingeneral should find wide application for joining steel, cast iron orcuprous members one to another, and for protecting such members fromundue wear by the provision thereon of deposits of the alloy of theinvention.

I claim:

1. A copper base alloy containing 23% to 30% nickel; 25% to 30% zinc; 5%to 11% tin; 0.01% to 0.5% silicon; the remainder substantially allcopper, the sum of the zinc and tin contents being to 41% of the alloy.

2. A copper base alloy containing 25% to 27% nickel; 29% to 33% zinc; 3%to 10% tin; 0.2% to 0.4% silicon; the remainder substantially all 4copper, the sum of the zinc and tin contents being 37% to 41% of thealloy.

3. A copper base alloy containing 25% to 27% nickel; 30% to 32% zinc;8.5% to 9.5% tin; 0.2% to 0.4% silicon; the remainder copper; the sum ofthe zinc and tin contents being less than 41% of the alloy.

4. A welding rod composed of a copper base alloy containing 23% to 30%nickel; 25% to 30% zinc; 5% to 11% tin; 0.01% to 0.5% silicon; theremainder substantially all copper, the sum of the zinc and tin contentsbeing 35% to 41% of the alloy.

5. A welding rod composed of a copper base alloy containing 25% to 27%nickel; 29% to 33% Zinc; 8% to 10% tin; 0.2 to 0.4% silicon; theremainder substantially all copper, the sum of the zinc and tin contentsbeing 37% to 41% of the alloy.

6. A welding rod composed of a copper base alloy containing 25% to 27%nickel; 30% to 32% zinc; 8.5% to 9.5% tin; 0.2% to 0.4% silicon; theremainder copper; the sum of the zinc and tin contents being less than41% of the alloy.

7. A metal article required during its normal use to resist wear, atleast the surface portions of said article exposed to wear, beingcomposed of a copper base alloy containing 23 to 30 nickel; 25% to 30%zinc; 5% to 11% tin; 0.01% to 0.5% silicon; the remainder substantiallyall copper, the sum of the zinc and tin contents being 35% to 41% of thealloy.

KENNETH H. KOOPMAN.

REFERENCES CITED FOREIGN PATENTS Country Date Great Britain Apr. 22,1926 OTHER. REFERENCES Journal of American Welding Society, Dec. 1928,page 9.

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